public class TestSimpleBuilder {

    public static void main(String[] args) {

        SimpleBuilder simpleBuilder = new SimpleBuilder(new Homework());

        simpleBuilder.buildEasyQc("简单题目");
        simpleBuilder.buildNormalQc("标准难度题目");
        simpleBuilder.buildHardQc("高难度题目");
        Homework homework = simpleBuilder.build();

        StringBuilder sb = new StringBuilder();
        sb.append(null == homework.getEasyQc() ? "" : homework.getEasyQc() + ",");
        sb.append(null == homework.getNormalQc() ? "" : homework.getNormalQc() + ",");
        sb.append(null == homework.getHardQc() ? "" : homework.getHardQc());

        System.out.println("我的家庭作业有：" + sb.toString());
    }
}